Redis命令-集合-sdiff
原文
http://redis.io/commands/sdiff
简介
Subtract multiple sets.
多个集合的差集。
语法
SDIFF key [key ...]
版本
Available since 1.0.0.
自1.0.0版本可用。
时间复杂度
Time complexity: O(N) where N is the total number of elements in all given sets.
O(N):N是所有给定集合中元素的总数。
描述
Returns the members of the set resulting from the difference between the first set and all the successive sets.
返回在第一个集合中存在,但是在后面的集合中都不存在的元素。
For example:
key1 = {a,b,c,d}
key2 = {c}
key3 = {a,c,e}
SDIFF key1 key2 key3 = {b,d}
Keys that do not exist are considered to be empty sets.
不存在的key被认为是空集合。
返回值
Array reply: list with members of the resulting set.
Array:结果集合的成员列表。
例子
redis> SADD key1 "a"
(integer) 1
redis> SADD key1 "b"
(integer) 1
redis> SADD key1 "c"
(integer) 1
redis> SADD key2 "c"
(integer) 1
redis> SADD key2 "d"
(integer) 1
redis> SADD key2 "e"
(integer) 1
redis> SDIFF key1 key2
1) "b"
2) "a"
redis>